Copper(II) sulfate, also known as copper sulphate, is an
inorganic compound
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...
with the
chemical formula
In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...
. It forms hydrates , where ''n'' can range from 1 to 7. The pentahydrate (''n'' = 5), a bright blue crystal, is the most commonly encountered hydrate of copper(II) sulfate. Older names for the pentahydrate include blue vitriol, bluestone, vitriol of copper,
[Antoine-François de Fourcroy, tr. by Robert Heron (1796) "Elements of Chemistry, and Natural History: To which is Prefixed the Philosophy of Chemistry". J. Murray and others, Edinburgh. Page 348.] and Roman vitriol.
[Oxford University Press,]
Roman vitriol
, Oxford Living Dictionaries. Accessed on 2016-11-13 It
exothermically dissolves in water to give the
aquo complex
In chemistry, metal aquo complexes are coordination compounds containing metal ions with only water as a ligand. These complexes are the predominant species in aqueous solutions of many metal salts, such as metal nitrates, sulfates, and perchlorat ...
, which has
octahedral molecular geometry
In chemistry, octahedral molecular geometry, also called square bipyramidal, describes the shape of compounds with six atoms or groups of atoms or ligands symmetrically arranged around a central atom, defining the vertices of an octahedron. The oc ...
. The structure of the solid pentahydrate reveals a polymeric structure wherein copper is again octahedral but bound to four water ligands. The centers are interconnected by sulfate anions to form chains.
Anhydrous
A substance is anhydrous if it contains no water. Many processes in chemistry can be impeded by the presence of water; therefore, it is important that water-free reagents and techniques are used. In practice, however, it is very difficult to achie ...
copper sulfate is a light grey powder.
Preparation and occurrence
![Synthesizing Copper Sulfate](https://upload.wikimedia.org/wikipedia/commons/8/88/Synthesizing_Copper_Sulfate.jpg)
Copper sulfate is produced industrially by treating copper metal with hot concentrated
sulfuric acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...
or copper oxides with dilute sulfuric acid. For laboratory use, copper sulfate is usually purchased. Copper sulfate can also be produced by slowly
leaching
Leaching is the loss or extraction of certain materials from a carrier into a liquid (usually, but not always a solvent). and may refer to:
* Leaching (agriculture), the loss of water-soluble plant nutrients from the soil; or applying a small amou ...
low-grade
copper ore
Following is a list of minerals that serve as copper ores in the copper mining
Copper extraction refers to the methods used to obtain copper from its ores. The conversion of copper consists of a series of physical and electrochemical proces ...
in air; bacteria may be used to hasten the process.
Commercial copper sulfate is usually about 98% pure copper sulfate, and may contain traces of water. Anhydrous copper sulfate is 39.81 percent copper and 60.19 percent sulfate by mass, and in its blue, hydrous form, it is 25.47% copper, 38.47% sulfate (12.82% sulfur) and 36.06% water by mass. Four types of
crystal size
Particle size is a notion introduced for comparing dimensions of solid particles ('' flecks''), liquid particles (''droplets''), or gaseous particles ('' bubbles''). The notion of particle size applies to particles in colloids, in ecology, in gr ...
are provided based on its usage: large crystals (10–40 mm), small crystals (2–10 mm), snow crystals (less than 2 mm), and windswept powder (less than 0.15 mm).
Chemical properties
Copper(II) sulfate pentahydrate
decomposes before melting. It loses two water molecules upon heating at , followed by two more at and the final water molecule at .
The chemistry of aqueous copper sulfate is simply that of copper
aquo complex
In chemistry, metal aquo complexes are coordination compounds containing metal ions with only water as a ligand. These complexes are the predominant species in aqueous solutions of many metal salts, such as metal nitrates, sulfates, and perchlorat ...
, since the sulfate is not bound to copper in such solutions. Thus, such solutions react with concentrated
hydrochloric acid
Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid
Acid strength is the tendency of an acid, symbol ...
to give
tetrachlorocuprate(II):
:
Similarly treatment of such solutions with zinc gives metallic copper, as described by this simplified equation:
:
A further illustration of such
"single metal replacement reactions" occurs when a piece of iron is submerged in a solution of copper sulfate:
:
In high school and general chemistry education, copper sulfate is used as an electrolyte for
galvanic cell
A galvanic cell or voltaic cell, named after the scientists Luigi Galvani and Alessandro Volta, respectively, is an electrochemical cell in which an electric current is generated from spontaneous Oxidation-Reduction reactions. A common apparatus ...
s, usually as a cathode solution. For example, in a zinc/copper cell, copper ion in copper sulfate solution absorbs electron from zinc and forms metallic copper.
:, E
°cell = 0.34 V
Copper sulfate is commonly included in teenager
chemistry set
A chemistry set is an educational toy allowing the user (typically a teenager) to perform simple chemistry experiments.
History
Forerunners
The forerunners of the chemistry set were 17th century books on "natural magick", "which all exce ...
s and undergraduate experiments. It is often used to grow crystals in
school
A school is an educational institution designed to provide learning spaces and learning environments for the teaching of students under the direction of teachers. Most countries have systems of formal education, which is sometimes compuls ...
s and in
copper plating
Copper electroplating is the process of electroplating a layer of copper onto the surface of a metal object. Copper is used both as a standalone coating and as an undercoat onto which other metals are subsequently plated. The copper layer can be de ...
experiments, despite its toxicity. Copper sulfate is often used to demonstrate an
exothermic reaction
In thermochemistry, an exothermic reaction is a "reaction for which the overall standard enthalpy change Δ''H''⚬ is negative." Exothermic reactions usually release heat. The term is often confused with exergonic reaction, which IUPAC defines ...
, in which
steel wool or
magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...
ribbon is placed in an
aqueous solution
An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCl), in water would be re ...
of . It is used to demonstrate the principle of
mineral hydration
In chemistry, mineral hydration is an inorganic chemical reaction which adds water to the crystal structure of a mineral, usually creating a new mineral, usually called a ''hydrate''.
In geological terms, the process of mineral hydration is know ...
. The
pentahydrate
In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was underst ...
form, which is blue, is heated, turning the copper sulfate into the anhydrous form which is white, while the water that was present in the pentahydrate form evaporates. When water is then added to the anhydrous compound, it turns back into the pentahydrate form, regaining its blue color. Copper(II) sulfate pentahydrate can easily be produced by crystallization from solution as copper(II) sulfate, which is
hygroscopic
Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance ...
.
Uses
As a fungicide and herbicide
Copper sulfate has been used for control of
algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...
in lakes and related fresh waters subject to
eutrophication
Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytopla ...
. It "remains the most effective algicidal treatment".
Bordeaux mixture
Bordeaux mixture (also called ''Bordo Mix'') is a mixture of copper(II) sulphate (CuSO4) and quicklime ( Ca O) used as a fungicide. It is used in vineyards, fruit-farms and gardens to prevent infestations of downy mildew, powdery mildew and other ...
, a suspension of copper(II) sulfate () and
calcium hydroxide
Calcium hydroxide (traditionally called slaked lime) is an inorganic compound with the chemical formula Ca( OH)2. It is a colorless crystal or white powder and is produced when quicklime (calcium oxide) is mixed or slaked with water. It has m ...
(), is used to control fungus on
grape
A grape is a fruit, botanically a berry, of the deciduous woody vines of the flowering plant genus ''Vitis''. Grapes are a non- climacteric type of fruit, generally occurring in clusters.
The cultivation of grapes began perhaps 8,000 years ago, ...
s,
melon
A melon is any of various plants of the family Cucurbitaceae with sweet, edible, and fleshy fruit. The word "melon" can refer to either the plant or specifically to the fruit. Botanically, a melon is a kind of berry, specifically a "pepo". The ...
s, and other
berries
A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet, sour or tart, and do not have a stone or pit, although many pips or seeds may be present. Common examples are strawberries, raspb ...
. It is produced by mixing a water solution of copper sulfate and a suspension of
slaked lime
Calcium hydroxide (traditionally called slaked lime) is an inorganic compound with the chemical formula Ca( OH)2. It is a colorless crystal or white powder and is produced when quicklime (calcium oxide) is mixed or slaked with water. It has ma ...
.
A dilute solution of copper sulfate is used to treat
aquarium
An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...
fishes for parasitic infections, and is also used to remove snails from aquariums and zebra mussels from water pipes. Copper ions are highly toxic to fish, however. Most species of algae can be controlled with very low concentrations of copper sulfate.
Analytical reagent
Several chemical tests utilize copper sulfate. It is used in
Fehling's solution
In organic chemistry, Fehling's solution is a chemical reagent used to differentiate between water-soluble carbohydrate and ketone () functional groups, and as a test for reducing sugars and non-reducing sugars, supplementary to the Tollens' reag ...
and
Benedict's solution to test for
reducing sugar
A reducing sugar is any sugar that is capable of acting as a reducing agent. In an alkaline solution, a reducing sugar forms some aldehyde or ketone, which allows it to act as a reducing agent, for example in Benedict's reagent. In such a react ...
s, which reduce the soluble blue copper(II) sulfate to insoluble red
copper(I) oxide
Copper(I) oxide or cuprous oxide is the inorganic compound with the formula Cu2O. It is one of the principal oxides of copper, the other being or copper(II) oxide or cupric oxide (CuO). This red-coloured solid is a component of some antifoulin ...
. Copper(II) sulfate is also used in the
Biuret reagent to test for proteins.
Copper sulfate is used to test blood for
anemia
Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, th ...
. The blood is dropped into a solution of copper sulfate of known
specific gravity
Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water (molecule), wa ...
—blood with sufficient
hemoglobin
Hemoglobin (haemoglobin BrE) (from the Greek word αἷμα, ''haîma'' 'blood' + Latin ''globus'' 'ball, sphere' + ''-in'') (), abbreviated Hb or Hgb, is the iron-containing oxygen-transport metalloprotein present in red blood cells (erythrocyte ...
sinks rapidly due to its density, whereas blood which sinks slowly or not at all has an insufficient amount of hemoglobin.
In a
flame test
A flame test is an analytical procedure used in chemistry to detect the presence of certain elements, primarily metal ions, based on each element's characteristic flame emission spectrum (which may be affected by the presence of chloride io ...
, the copper
ion
An ion () is an atom or molecule with a net electrical charge.
The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...
s of copper sulfate emit a deep green light, a much deeper green than the flame test for
barium
Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element.
Th ...
.
Organic synthesis
Copper sulfate is employed at a limited level in
organic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...
. The anhydrous salt is used as a dehydrating agent for forming and manipulating
acetal
In organic chemistry, an acetal is a functional group with the connectivity . Here, the R groups can be organic fragments (a carbon atom, with arbitrary other atoms attached to that) or hydrogen, while the R' groups must be organic fragments no ...
groups.
The hydrated salt can be intimately mingled with
potassium permanganate
Potassium permanganate is an inorganic compound with the chemical formula KMnO4. It is a purplish-black crystalline salt, that dissolves in water as K+ and , an intensely pink to purple solution.
Potassium permanganate is widely used in the c ...
to give an oxidant for the conversion of primary alcohols.
Rayon production
Reaction with
ammonium hydroxide
Ammonia solution, also known as ammonia water, ammonium hydroxide, ammoniacal liquor, ammonia liquor, aqua ammonia, aqueous ammonia, or (inaccurately) ammonia, is a solution of ammonia in water. It can be denoted by the symbols NH3(aq). Although ...
yields
tetraamminecopper(II) sulfate
Tetraamminecopper(II) sulfate is the salt with the formula u(NH3)4O4·H2O. This dark blue to purple solid is a salt of the metal complex u(NH3)4(H2O)sup>2+. It is closely related to Schweizer's reagent, which is used for the production of cell ...
or
Schweizer's reagent
Schweizer's reagent is the metal ammine complex with the formula u(NH3)4(H2O)2OH)2. This deep-blue compound is used in purifying cellulose.
It is prepared by precipitating copper(II) hydroxide from an aqueous solution of copper sulfate using sod ...
which was used to dissolve
cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall ...
in the industrial production of
Rayon
Rayon is a semi-synthetic fiber, made from natural sources of regenerated cellulose, such as wood and related agricultural products. It has the same molecular structure as cellulose. It is also called viscose. Many types and grades of viscose f ...
.
Niche uses
Copper(II) sulfate has attracted many niche applications over the centuries. In industry copper sulfate has multiple applications. In printing it is an additive to book-binding pastes and glues to protect paper from insect bites; in building it is used as an additive to concrete to improve water resistance and discourage anything from growing on it. Copper sulfate can be used as a coloring ingredient in artworks, especially glasses and potteries.
Copper sulfate is also used in firework manufacture as a blue coloring agent, but it is not safe to mix copper sulfate with chlorates when mixing firework powders.
![Copper sulfate etching bath](https://upload.wikimedia.org/wikipedia/commons/f/fa/Copper_sulfate_etching_bath.JPG)
Copper sulfate was once used to kill
bromeliads
The Bromeliaceae (the bromeliads) are a family of monocot flowering plants of about 80 genera and 3700 known species, native mainly to the tropical Americas, with several species found in the American subtropics and one in tropical west Africa, ...
, which serve as mosquito breeding sites. Copper sulfate is used as a molluscicide to treat
bilharzia
Schistosomiasis, also known as snail fever, bilharzia, and Katayama fever, is a disease caused by parasitic flatworms called schistosomes. The urinary tract or the intestines may be infected. Symptoms include abdominal pain, diarrhea, bloody ...
in tropical countries.
*Art
In 2008, the artist
Roger Hiorns
Roger Hiorns (born 1975) is a British Contemporary artist based in London. His primary media is sculpture and installation, using a wide variety of materials, including metals, wood and plastics. He also works in the media of video and photograp ...
filled an abandoned waterproofed
council flat
A council house is a form of British public housing built by local authorities. A council estate is a building complex containing a number of council houses and other amenities like schools and shops. Construction took place mainly from 1919 a ...
in London with 75,000 liters of copper(II) sulfate water solution. The solution was left to crystallize for several weeks before the flat was drained, leaving
crystal
A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...
-covered walls, floors and ceilings. The work is titled ''Seizure''. Since 2011, it has been on exhibition at the
Yorkshire Sculpture Park
The Yorkshire Sculpture Park (YSP) is an art gallery, with both open-air and indoor exhibition spaces, in West Bretton, Wakefield, in West Yorkshire, England. It shows work by British and international artists, including Henry Moore and Barbar ...
.
*Etching
Copper(II) sulfate is used to etch zinc or copper plates for
intaglio printmaking.
It is also used to etch designs into copper for jewelry, such as for
Champlevé
Champlevé is an enamelling technique in the decorative arts, or an object made by that process, in which troughs or cells are carved, etched, die struck, or Casting (metalworking), cast into the surface of a metal object, and filled with vitre ...
.
*Dyeing
Copper(II) sulfate can be used as a
mordant
A mordant or dye fixative is a substance used to set (i.e. bind) dyes on fabrics by forming a coordination complex with the dye, which then attaches to the fabric (or tissue). It may be used for dyeing fabrics or for intensifying stains in ...
in vegetable
dyeing
Dyeing is the application of dyes or pigments on textile materials such as fibers, yarns, and fabrics with the goal of achieving color with desired color fastness. Dyeing is normally done in a special solution containing dyes and particular ...
. It often highlights the green tints of the specific dyes.
*Electronics
An aqueous solution of copper(II) sulfate is often used as the resistive element in
liquid resistor
A liquid resistor is an electrical resistor in which the resistive element is a solution. Fixed-value liquid resistors are typically used where very high power dissipation is required. They are used in the rotor circuits of large slip ring indu ...
s.
Other forms of copper sulfate
Anhydrous copper(II) sulfate can be produced by dehydration of the commonly available pentahydrate copper sulfate. In nature, it is found as the very rare mineral known as
chalcocyanite. The pentahydrate also occurs in nature as
chalcanthite
Chalcanthite (, ) is a richly colored blue-green water-soluble sulfate mineral . It is commonly found in the late-stage oxidation zones of copper deposits. Due to its ready solubility, chalcanthite is more common in arid regions.
Chalcanthite i ...
. Other rare copper sulfate minerals include
bonattite (trihydrate),
boothite
Boothite is a very rare, naturally occurring mineral containing hydrated copper sulfate: Cu(SO4)·7H2O. It was discovered in the Leona Heights region near Oakland, California
Oakland is the largest city and the county seat of Alameda County, ...
(heptahydrate), and the monohydrate compound poitevinite.
There are numerous other, more complex, copper(II) sulfate minerals known, with environmentally important basic copper(II) sulfates like langite and posnjakite.
File:Copper sulfate anhydrous.jpg, Anhydrous
File:Copper(II)-sulfate-3D-vdW.png, Space-filling model anhydrous
File:Arseniosiderite-Boothite-sea69a.jpg, The rare mineral ''boothite'' ()
Toxicological effects
Copper(II) salts have an
LD50
In toxicology, the median lethal dose, LD50 (abbreviation for "lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 is a toxic unit that measures the lethal dose of a toxin, radiation, or pathogen. The value of LD50 for a substance is the ...
of 100 mg/kg.
It is harmless enough to be a routine component of high school experiments and to be used widely in swimming lakes to control algae.
Copper(II) sulfate was used in the past as an
emetic
Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose.
Vomiting can be the result of ailments like food poisoning, gastroenteri ...
.
It is now considered too toxic for this use.
It is still listed as an
antidote
An antidote is a substance that can counteract a form of poisoning. The term ultimately derives from the Greek term φάρμακον ἀντίδοτον ''(pharmakon) antidoton'', "(medicine) given as a remedy". Antidotes for anticoagulants are s ...
in the
World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of h ...
's
Anatomical Therapeutic Chemical Classification System
The Anatomical Therapeutic Chemical (ATC) Classification System is a drug classification system that classifies the active ingredients of drugs according to the organ or system on which they act and their therapeutic, pharmacological and chemical ...
.
See also
*
Chalcanthum
*
Vitriol
Vitriol is the general chemical name encompassing a class of chemical compound comprising sulfates of certain metalsoriginally, iron or copper. Those mineral substances were distinguished by their color, such as green vitriol for hydrated iron( ...
References
Bibliography
*
External links
*
*
*
National Pollutant Inventory – Copper and compounds fact sheet
{{DEFAULTSORT:Copper(Ii) Sulfate
Copper(II) compounds
Sulfates
Desiccants
Herbicides